<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
</body>
<script>
    function Person(name, age) {
        this.name = name;
        this.age = age;
    }

    Person.prototype.hi = function () {
      console.log("hi, my name is " + this.name + " I'm " + this.age);
    };
    Person.prototype.walk = function () {
      console.log(this.name + " is walking");
    };
    Person.prototype.ARMS = 2;

    function Student(name ,age, className) {
        Person.call(this, arguments[0], arguments[1]);
        this.className = className;
    }

    Student.prototype = Object.create(Person.prototype);
    Student.prototype.constructor = Student;

    Student.prototype.hi = function () {
        console.log("hi, my name is " + this.name + " I'm " + this.age + " at " + this.className);
    };
    Student.prototype.learn = function (something) {
        console.log(this.name + " is learning " + something);
    }
    Student.prototype.test = "123";

    var cc = new Student("cc", 32, "class 3");
    cc.hi();
    cc.walk();
    cc.learn("math");
    console.log(cc.ARMS + "  " + cc.test);
</script>
</html>